avcodec/utils: Also free encoder extradata on avcodec_open2() error

It is owned by libavcodec for encoders.
Signed-off-by: NAndreas Rheinhardt <andreas.rheinhardt@gmail.com>

libavcodec/utils.c

@@ -1034,11 +1034,15 @@ free_and_end:
         av_opt_free(avctx->priv_data);
     av_opt_free(avctx);
 
+    if (av_codec_is_encoder(avctx->codec)) {
 #if FF_API_CODED_FRAME
 FF_DISABLE_DEPRECATION_WARNINGS
     av_frame_free(&avctx->coded_frame);
 FF_ENABLE_DEPRECATION_WARNINGS
 #endif
+        av_freep(&avctx->extradata);
+        avctx->extradata_size = 0;
+    }
 
     av_dict_free(&tmp);
     av_freep(&avctx->priv_data);